Zorst Ring Thing

[WannaBeDude]

2T 125 have 2 rubber rings that fit inside the pipe just before engine, one small and one big one, im missing one, what effect would or could this have ?
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[mentalboy]

C'mon you know the drill. Make, model, year.
It's not unusual to find different bikes with non - copper header gaskets, however when you say two different sizes do you mean diameters? Sounds like one is original and other a bodge if so.
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[WannaBeDude]

2009 125 Raptor ( Mito ) - they were new rubber rings for pipe engine end, for within pipe, the larger one has been fitted on the outside of the pipe, so where its supposed to be there is not one there, or maybe there is, but I never saw one, even with grease the larger one would not seat, supposed to be awkward fit.

May be PJME gave me wrong size, doubtful.

Just wondering effects, whether to refit one, or leave until I buy a new pipe maybe next year.

Jetting and plug chops are A ok.
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[mentalboy]

Sounds like it's only there to help stop blowing. I'd try it and see.Worst that can happen is it'll chuck fumes out.
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[WannaBeDude]

The rings are for INSIDE the pipe, looking for a definitive answer as to what they do, and what not having the larger one does.
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[mentalboy]

Ok, we'll start again. You are saying that these are not exhaust gaskets right?
If not I would speculate that they are something to do with restricting it. In which case I would have thought that one of these would be conical.
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[WannaBeDude]

Tbf - ive said what their made of and where their supposed to go -
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[mentalboy]

[nowhere.elysium]

I'd imagine they're vitron rubber, which is (IIRC) treated to survive high temperatures. As for what effect it'd have; as with all two-strokes, they're very sensitive to changes in the incoming and outgoing flow of gases, so I'd imagine you'd potentially lose a bit of power, and if it flowed extra gas beyond a certain threshold, it might start to get a bit lean.

However, this post should be taken with a pinch of salt, since I've never actually owned or ridden a two-stroke; a fact that I lament, but can't really be bothered to remedy.
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[mentalboy]

[WannaBeDude]

Well if I put the larger one back in I will have to downjet then, running 132 main - with str through end can, standard is 120.
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[WannaBeDude]

Basically if its fine without, then 132 main is ok with me ... pulls ok - no issues there - so -
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[WannaBeDude]

[WannaBeDude]

[mentalboy]

Cov - dude take a chill pill.
It's a two stroke not a clockwork hydrogen processing plant!

So we have established that you have two rubber rings inside the pipe, they're not exhaust header gaskets, and one of them doesn't fit.
What was the set up before you removed said exhaust pipe?
You'll be ok running up jetted carb at the moment because the stock exhaust has been replaced with a straight through which will make bike run leaner.
A plug chop will confirm that your mixture is ok, or not.
If I read you right then the larger one was never there, which would probably mean it was binned when someone was beefing up performance.
Because of the importance of exhaust diameter/ pipe length for a two stroke to run well, it would suggest to me that Cagiva designed set up for its optimal performance and added a ring in the pipe to make it conform to certain markets. Ones with bhp restrictions get rings, ones without don't.
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[WannaBeDude]

Think the rings are to help seal pipe to manifold

Am chilled. have asked - before, now and elsewhere, no definitive answer ...
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[mentalboy]

[WannaBeDude]

Pic on here scroll down a bit ...

https://www.125ccsportsbikes.com/forums/index.php?showtopic=99666
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[mentalboy]

So does the larger one fit into a recess or a groove? If it would fit that is!

Edit: I hope that pics not yours, it's hanging!
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[WannaBeDude]

Below pic is a diagram, fits into groove
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[mentalboy]

I think you'll just have to keep fighting that ring into place, it looks like it is only a gasket to prevent blowing. It'll make it noisy without and may affect smooth running, I doubt very much if it's the wrong size, sounds like you're not the only one to have grief fighting it into place.
You could try heating pipe to make it expand, best way if you are careful would be to put pipe in place and run up engine. Best way to hold pipe after heat would be to get a solder mat and wrap it round pipe.
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[WannaBeDude]

A competent person will be doing it in future, so you think come new pipe time, buy some new rings and use them.?

The bike is loud, as the end can is str through, but still has baffles.

Not sure if more noise is present as a result of the missing ring.

Bike was checked as not blowing.

On decoking pipe / all new gaskets were put on using paste, same time was the new can.

As a result of the above, jetting was changed a few times until plug chops were good.

Whilst arrow stated 120 jet for their can, I think they mean their can plus pipe.

So I now believe, new arrow pipe and gaskets, decoke and rejet is the way forward ?

And thanks for your help and time dude !
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[mentalboy]

No problems
What is wrong with the current pipe, is it not an Arrow? It may help final max output values but at the end of the day you could end up spending silly money in order to achieve a barely noticeable improvement in performance.
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[WannaBeDude]

Its only the pipe which will be about 170 quid or so, the current pipe is very good, but weighs a ton, will get circa 40 quid plus for it to put towards new pipe.

Its merely come decoke time will make the upgrade, arrow pipe is a lot less weight, as was the can upgrade from standard. The small extra top end will help a tad, I don't mind suffering less midrange as a result.

Its easily done and jeted, would get Jolly etc, but will keep it nice and simple ish.
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